Integration of virtual channels from doppler division multiplex (ddm) fmcw radar signal

Abstract

Some aspects of the present disclosure relate a radar system including a radio frequency (RF) receiver that receives radar data on a plurality of receive antennas. A fast Fourier transform (FFT) circuit is coupled to the RF receiver. The FFT circuit performs a FFT on the radar data to provide a plurality of Range-Doppler coordinate pairs that pertain to the plurality of receive antennas. An integration block is coupled to the FFT circuit, and sums multiple Range-Doppler coordinate pairs for respective Doppler bins to provide a plurality of Range-Doppler sums. The integration block also sums multiple Range-Doppler sums within the plurality of Range-Doppler sums to provide an integration result. The multiple Range-Doppler coordinate pairs that are summed are spaced apart from one another by a Doppler offset.

What is claimed is: 
     
         1 . A method, comprising:
 receiving an incoming radar signal in response to an outgoing radar signal, the incoming radar signal received via a plurality of receive antennas;   performing a fast Fourier transform (FFT) on the incoming radar signal to provide a stream of complex values describing a plurality of Range-Doppler coordinate pairs;   determining a plurality of Range-Doppler sums by summing complex values from the stream of complex values, wherein a Range-Doppler sum corresponds to a sum over the plurality of receive antennas for a Range-Doppler bin; and   determining an integration result by summing multiple Range-Doppler sums of the plurality of Range-Doppler sums, wherein the multiple Range-Doppler sums that are summed to provide the integration result are spaced apart from one another by an offset.   
     
     
         2 . The method of  claim 1 , wherein the outgoing radar signal is transmitted via a transmission antenna according to a predetermined modulation, and the offset is based on the predetermined modulation. 
     
     
         3 . The method of  claim 1 , wherein the multiple Range-Doppler sums that are summed include a first Range-Doppler sum and a second Range-Doppler sum, wherein the offset is a first number of Doppler bins separating the first Range-Doppler sum from the second Range-Doppler sum. 
     
     
         4 . The method of  claim 3 , wherein the multiple Range-Doppler sums that are summed include a third Range-Doppler sum, wherein the first number of Doppler bins also separates the second Range-Doppler sum from the third Range-Doppler sum. 
     
     
         5 . The method of  claim 3 , further comprising:
 determining whether a target is present based on the integration result.   
     
     
         6 . The method of  claim 1 , wherein determining the plurality of Range-Doppler sums includes multiplying Range-Doppler values for the plurality of receive antennas by a plurality of coefficients, respectively, for the plurality of receive antennas, respectively. 
     
     
         7 . A radar system:
 a radio frequency (RF) receiver configured to receive radar data via a plurality of receive antennas;   a fast Fourier transform (FFT) circuit coupled to the RF receiver, the FFT circuit configured to perform a FFT on the radar data to provide a plurality of Range-Doppler coordinate pairs;   an integration block coupled to the FFT circuit, the integration block configured to sum multiple Range-Doppler coordinate pairs for respective Doppler bins to provide a plurality of Range-Doppler sums, and further configured to sum multiple Range-Doppler sums within the plurality of Range-Doppler sums to provide an integration result, wherein the multiple Range-Doppler coordinate pairs that are summed are spaced apart from one another by a Doppler offset.   
     
     
         8 . The radar system of  claim 7 , further comprising:
 a target detector coupled to the integration block and configured to determine whether a target is present based on the integration result.   
     
     
         9 . The radar system of  claim 8 , wherein the integration block comprises:
 a first multiplexer having a first input, a second input, and an output, the first input of the first multiplexer coupled to the FFT circuit;   a multiplier having a first input, a second input, and an output, the first input of the multiplier coupled to the output of the first multiplexer; and   an adder having a first input, a second input, and an output, the first input of the adder coupled to the output of the multiplier, and the output of the adder coupled to an input of the target detector.   
     
     
         10 . The radar system of  claim 7 , wherein the integration block is configured to sum a first subset of Range-Doppler coordinate pairs each having a first Doppler value within the plurality of Range-Doppler sums to provide a first Range-Doppler sum, and sum a second subset of Range-Doppler coordinate pairs each having a second Doppler value within the plurality of Range-Doppler sums to provide a second Range-Doppler sum. 
     
     
         11 . The radar system of  claim 10 , wherein the first Doppler value is spaced apart from the second Doppler value by the Doppler offset. 
     
     
         12 . The radar system of  claim 10 , wherein the integration block is configured to sum the first Range-Doppler sum and the second Range-Doppler sum to provide the integration result. 
     
     
         13 . The radar system of  claim 10 , wherein the integration block is further configured to sum a third subset of Range-Doppler coordinate pairs each having a third Doppler value within the plurality of Range-Doppler sums to provide a third Range-Doppler sum, and sum the first, second, and third Range-Doppler sums to provide the integration result. 
     
     
         14 . The radar system of  claim 13 , wherein the first Doppler value and second Doppler value are spaced apart from one another by the Doppler offset, and the second Doppler value and third Doppler value are spaced apart from one another by the Doppler offset. 
     
     
         15 . The radar system of  claim 7 , wherein the radar system is a frequency modulated continuous wave (FMCW) radar system. 
     
     
         16 . A radar system:
 a radio frequency (RF) receiver including a plurality of receive antennas;   a fast Fourier transform (FFT) circuit coupled to the RF receiver;   a target detector coupled to the FFT circuit; and   an integration block coupled between the FFT circuit and the target detector, the integration block comprising:
 a first multiplexer having a first input, a second input, and an output, the first input of the first multiplexer coupled to the FFT circuit; 
 a multiplier having a first input, a second input, and an output, the first input of the multiplier coupled to the output of the first multiplexer; and 
 an adder having a first input, a second input, and an output, the first input of the adder coupled to the output of the multiplier, and the output of the adder coupled to an input of the target detector. 
   
     
     
         17 . The radar system of  claim 16 , further comprising:
 a coefficient memory configured to store a plurality of coefficients for the plurality of receive antennas, respectively; wherein the second input of the multiplier is coupled to the coefficient memory.   
     
     
         18 . The radar system of  claim 16 , wherein the integration block further comprises:
 a second multiplexer having a first input, a second input, and an output, the first input of the second multiplexer coupled to the output of the adder, and the output of the second multiplexer coupled to the second input of the adder.   
     
     
         19 . The radar system of  claim 16 , wherein the second input of the first multiplexer is coupled to the output of the adder. 
     
     
         20 . The radar system of  claim 16 , wherein the radar system is a frequency modulated continuous wave (FMCW) radar system.